This invention relates to a process for producing granulated strontium carbonate, to the subsequently obtained granulated strontium carbonate and to its use in the glass industry.
In the glass industry, strontium carbonate is used, for example, for the manufacturing of front panes for television sets. In this manner, x-rays from cathode ray tubes may be absorbed.
The production of pure strontium carbonate takes place by means of the precipitation of strontium hydroxides or strontium sulfide with carbon dioxide or carbonates. In the case of this process, powders with very fine particles are obtained which are hard to process. Up to now, the granulation of these powders has normally been carried out by sintering at approximately 800.degree. C. in rotary furnaces. This process is very energy-intensive, and also results in the product becoming contaminated with refractory materials.
U.S. Pat. No. 4,888,161 describes a process for granulating alkaline-earth metal carbonate in which a suspension of the carbonate is produced in water and a quantity of a deflocculating agent which is sufficient for the deflocculating of the carbonate is added, preferably alkali metal salts or ammonium salts of acrylic acid or methacrylic acid or of phosphoric acid or polyphosphoric acid. The liquified suspension will then be dried in a spray drier, and the resulting granulates will be heated to 600.degree. to 700.degree. C. The disadvantage in the case of this process is the addition of foreign ions.